This project will investigate racial and ethnic differences in physical activity (PA). This is important since PA has been shown to have a positive impact on health. Physical activity occurs during leisure-time, household work and market work. Prior studies show that whites engage in more leisure time PA than minorities. However, there is evidence that minorities engage in more PA at work. Less is known about PA differentials in household work and about total PA differentials. Prior studies of PA have relied largely on small esoteric samples or on one of three national datasets. These small samples are problematic since they cannot be generalized to the overall population. The national data sets are also problematic since they include reporting and recall errors, lack detailed information on the various types of PA and measure PA in relation to subjective categories which are open to individual interpretation. This project will improve on prior studies by employing the American Time Use Survey (ATUS) for a comprehensive examination of racial and ethnic differences in PA and an examination of the correlates of PA for specific race and ethnic subgroups. The ATUS is a large nationally-representative sample which includes extensive data on PA. These surveys include a detailed time diary and have undergone substantive field testing, and follow-up testing to ensure consistency. Multivariate analyses will investigate whether, and to what extent, the observed differences in the various types of PA are driven by differences in income and education, other demographics, environmental factors, occupation and industry selection, and other measures of individual heterogeneity. These estimates will be policy relevant since they will be useful in identifying public policies to promote PA within target groups. If there is significant variation in PA across race/ethnic groups, then these differences may also be contributing to the persistent racial disparities in health status, for which the underlying causes are not fully accounted. PUBLIC HEALTH RELEVANCE: This project will measure differences in physical activity by race and ethnic group. The factors contributing to any differentials will also be investigated. Since physical activity has been shown to have a positive effect on health, lower levels for minority groups would be a factor contributing to observed racial and ethnic health differentials.